Light emitting diode (LED) components, such as reflectors, reflector cups, and scramblers are typically formed from polymer compositions. LED applications require polymer compositions with good opacity and reflective properties. Various useful polymer compositions for LED applications are known, these ones usually include polycondensation polymers, such as polyphthalamides. One problem noted with the prior art compositions used in LED applications is yellowing upon heat aging.
LED components are exposed to elevated temperatures during the manufacturing process. For example, during the fabricating steps the LED components are heated to about 180° C. to cure an epoxy potting compound. The LED components are also exposed to temperatures above 260° C. while soldering operations are performed. In addition, while in use, LED components, such as automobile components, are routinely subjected to temperatures above 80° C. This exposure to high temperatures causes yellowing of polymer compositions used for forming LED components.
Another polymer composition used for LED components comprises polycarbonate. Polycarbonate compositions, however, soften when exposed to the epoxy curing and soldering temperatures. LED components formed from polycarbonate compositions would not retain their shape at these temperatures.
Yellowing is a particularly acute problem for blue light LEDs. Yellow surfaces absorb blue light. Thus, yellow reflectors absorb blue light rather and are, therefore, inefficient reflectors.